Issue: 01/14/04

Mission to Mars

Research could help future exploration of the red planet

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01/14/04

Paul Francuch

Space agency officials are happier these days than they’ve been in a long time.

NASA officials continue to herald the successful touchdown Jan. 3 of the Mars rover “Spirit” and they have their fingers crossed that its companion rover “Opportunity” will bounce happily to its red planet target come Jan. 24.

Morale at the agency was bolstered by President George Bush’s proposal to return astronauts to the Moon and ultimately fly on to Mars.

But that’s unlikely to happen for at least a decade, if that soon.

In the meantime, NASA scientists and engineers have ambitious plans on the drawing boards for future Mars missions using a new generation of mechanical devices, notably an exploratory vehicle that will “hop” around the planet, propelled by rocket engines using fuel derived from carbon dioxide in Mars’ atmosphere.

A unique piece of laboratory equipment at UIC may be a key to making it all happen.

“It’s designed as a small rocket that takes off, hops up and then comes down to a landing,” says Kenneth Brezinsky, professor of mechanical and industrial engineering, who was just awarded a three-year, $368,000 NASA grant to refine the state of chemical understanding needed to make the proposed “Mars Hopper” work.

“Solar cells on the hopper will electrolyze atmospheric carbon dioxide, breaking it up into carbon monoxide and oxygen” to use as fuel, explains Brezinsky.

Current rover vehicles have a range of only a few thousand feet.

“The ‘hops’ can be as far as four kilometers, so it could really cover a wide surface of Mars,” he says.

To accomplish this feat, NASA must better understand how to turn this low-grade fuel into a peak performer.

A small amount of hydrogen is necessary for optimum combustion, but exactly how much has yet to be determined.

Can the amount of necessary hydrogen be so minimal that it may be found on Mars? Or must a supply of hydrogen, or water to make hydrogen, be carried from Earth aboard the hopper to get the job done once it lands on Mars?

Brezinsky thinks he can find the answers using a custom-made instrument in his lab called a “very high pressure single pulse shock tube.”

The device is already used in ongoing National Science Foundation and U.S. Department of Energy-funded pollution research to help formulate cleaner burning diesel and gasoline engine fuels.

The device consists of a pair of tubes, a high-pressure gas driver and a lower-pressure driven section, separated by a metal diaphragm which, when it breaks under pressure, creates a shock wave that subjects chemical reactants to various test pressures and temperatures.

No other device anywhere can provide chemical analysis at the pressures reached in UIC’s shock tube.

“The reactant gases we’ll test will be carbon monoxide and oxygen,” says Brezinsky.

“We’ll subject it to high temperature and pressures, withdrawing samples and analyzing with gas chromatography, mass spectrometry, thermal conductivity detectors that allow us to monitor the amount of carbon monoxide left after a certain time period, the amount of oxygen and the amount of carbon dioxide that’s formed.

“If we add hydrogen, we can monitor the change in hydrogen, the change in water.

“And from the changes in these concentrations, as a function of temperatures, pressures and times, we then have data that allows us to determine the chemical kinetics of the mixture – which means, how the chemistry changes with time.

“Ultimately, the goal of this work is to use what we find to refine computer-based chemical kinetic models so that NASA will know they’re able to work at the high pressures and high temperatures relevant to the Martian hopper. Once we produce this model, based on the data, then it becomes the input for the hopper rocket engine design by the NASA scientists, influencing how long the engine combustor is, what the nozzle diameter will be and its shape.”

Brezinsky and his laboratory co-investigator Robert Tranter, a research assistant professor in mechanical engineering, will use the NASA project in teaching graduate students.

The students will modify the shock tube for the project using a newly installed device to measure temperatures optically, in conjunction with current chemical thermometers that determine temperature by monitoring chemical decay.

Brezinsky says scientists at NASA’s Glenn Research Center in Cleveland, Ohio, have already designed a Martian Hopper, but whether it is ever built will depend on NASA’s evaluation of its feasibility for exploration.

“They like to build the scientific base for many potential exploration devices, then make decisions. We’re part of building a scientific base that will contribute to the development of this device. But there may be other devices to replace the Mars rover,” he says.

Whatever NASA’s decision – which probably won’t come until years from now – Brezinsky plans to form an ongoing association with the agency to provide a research facility at UIC that will play an important role in future space exploration.

“This could end up in the building of a device that I could say, ‘I contributed to the chemistry of that explorer,’” he says.

“I find that very exciting.”

Below: An illustration of the Mars rover.
Illustration: JPL/NASA